In the field of flat X-ray detectors, the way to obtain sharp images, i.e. a high or an improved optical transfer function or a high or an improved modulation transfer function, when using thick scintillator layers is pixilation. The most applied scintillator, CsI:Tl, Thallium doped Caesium Iodide, is pixelated by giving it a needle-shape, micro columnar structure, during the thermal evaporation deposition, typical dimensions are a needle diameter of 7 μm and a needle height of up to 600 μm.
For other scintillator materials, pixilation by separating the individual scintillator pixels with a reflective material is known, but for the flat X-ray detector application requiring a pixel height to width ratio of 5 or more, this is not applicable.
US 2004 004 258 5 A1 relates to a method of fabricating an apparatus for an enhanced imaging sensor consisting of pixelated micro columnar scintillation film material for X-ray imaging comprising a scintillation substrate and a micro columnar scintillation film material in contact with the scintillation substrate.
US 2010 026 431 8 A1 describes scintillator-elements for use in X-ray detectors, the elements being shaped to ensure maximum absorption of the energy carried in by X-ray photons and to provide high position-resolution. Arrangements of such scintillator-elements in arrays and detector-systems comprising a plurality of arrays are described.
US 2011/0211668 A1 relates to a converter element for a radiation detector, which comprises at least two conversion cells that are at least partially separated from each other by intermediate separation walls which affect the spreading of electrical signals generated by incident radiation.
US 20050089142 A1 describes scintillator coatings having predetermined barrier protection, light transmission, and light reflection properties. These scintillators comprise: a scintillator material comprising a barrier coating disposed thereon, wherein the barrier coating: provides barrier protection to the scintillator material, is capable of transmitting light there through, and is capable of reflecting light back into the scintillator material.
WO 2013/015438 A2 describes a scintillator comprising multiple columnar portions which are stacked in a state in which end faces of the multiple columnar portions are partly offset with respect to each other.
US 2014/0175295 A1 describes a scintillator comprising a scintillator layer including a plurality of columnar crystals configured to convert radiation into light, and a covering layer configured to cover the scintillator layer, wherein the scintillator layer includes a protrusion. The protrusions are typically an abnormally growing portion generated by abnormal growth when the plurality of columnar crystals grow.